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How to create a source that is not affected by backpressure

I want to test some of the Akka stream features like conflate

. For this, I need to create a source that is not affected by back pressure in a simple unit test. Naive attempts like

Source.tick(1.milli, 1.milli, "tick").map(_ => Random.nextDouble())

do not work due to back pressure. OTOH over HTTP is probably overkill.

How to create a simple Source

unit test that is not affected by back pressure?

+3


source to share


1 answer


You can use Source.actorRef

which is by design and not backpressure. See example below:

  val actorRef: ActorRef = Source.actorRef(0, OverflowStrategy.dropNew)
      .map(_ => Random.nextDouble())
      .to(yourSink).run()

  system.scheduler.schedule(1.milli, 1.milli, actorRef, "tick")(system.dispatcher)


The bufferSize parameters and the overflow strategy are randomly selected here, you will need to adjust them to your test needs.

More details Source.actorRef

can be found in the docs .

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